The present invention relates to a filtering apparatus and method for cleaning industrial fluids used in industrial applications. In particular, it relates to a centrifugal separator for use in removing contaminants and cleaning industrial fluids and the method of using the centrifugal separator for cleaning the fluid.
Many industrial processes require suitable fluids for proper operation of the machines utilized in the process. For example, stamping operations require that the metal to be stamped be properly washed by a lubricating fluid. In stamping operation, the metal is sprayed or immersed in the fluid and after the washing operation, the fluid is scraped from the surface of the metal to remove contaminants, dirt, etc., present on the surface of the metal. The fluid is then recycled and returned to the equipment for further use in the process. Over time, the fluid becomes contaminated with heavy metals and particulate matter which can result in reduced life of the fluid and the apparatus. At present, such apparatus use cartridge type filters for removing contaminants from the fluid. While such filters are suitable for removing large particulate contaminants, smaller contaminants may pass through the filtering material and are able to continuously circulate through the system. Over time, in order to remove such contaminants, it may be necessary to replace the fluid and wash the system thoroughly. This results in down time for the apparatus and may significantly increase the cost of products produced by the apparatus.
Centrifuge filters have been utilized in certain automotive applications, particularly internal combustion engines such as are described in U.S. Pat. Nos. 4,492,631 and 4,165,032, the disclosures of which are incorporated herein by reference. U.S. Pat. No. 4,492,631 describes a centrifugal separator for separating contaminants from contaminated oil. The separator has an outer casing and a rotor within the casing mounted for rotation about a vertical axis. Oil under pressure enters the rotor at one end and exits the other end through jets into a chamber normally filled with air. As the oil passes through the jets, it causes the rotor to spin within the housing, causing a centrifugal force on the wall of the rotor that attracts the contaminants which adhere to the wall. The cleaned oil flows to the sump and is used in the lubricating of the engine. In order to maintain the flow of oil, it is necessary that the casing retain its air and not fill with oil. This is accomplished by supplying air under pressure to the interior of the casing by means of a float operated valve member that detects the level of oil in the casing. While such centrifugal separators have found use in internal combustion engines, they have not been adapted for other applications.
The present invention in one aspect provides for an improved method for cleaning industrial lubricants used in industrial processes. The method comprises providing a centrifugal separator apparatus connected as a bypass or in-line filter in the lubricating or washing fluid tank. The centrifugal separator has a casing and a rotor rotatably mounted in the casing. A centrifugal pump is provided between the tank and the inlet of the separator. A source of compressed air is provided connected to the casing of the separator. Some of the fluid from the tank is pumped by the centrifugal pump into the separator to cause the rotor to rotate and impinge the fluid on the casing at a rotational force of between about 1000 g and about 2000 g and clean the fluid. The cleaned fluid is returned to the tank. The volume of air in the casing is maintained by introduction of air into the casing by the source of compressed air. A control panel is provided to monitor the operation of the separator and control the pump and source of compressed air to maintain the rotational force of the separator within the range.
In an aspect of the invention there is provided a centrifugal separator apparatus for use as a bypass or in-line filter in cleaning fluid utilized in industrial applications. The apparatus includes a centrifugal separator having a casing and a rotor rotatably mounted in the casing. A centrifugal pump is provided between the tank and the inlet of the separator for pumping some of the fluid from the tank into the separator to cause the rotor to rotate and impinge the fluid on the casing at a rotational force of between about 1000 g and about 2000 g and clean the fluid. A source of compressed air is provided connected to the casing of the separator for maintaining the volume of air in the casing. A control panel is provided to monitor the operation of the separator and control the pump and source of compressed air to maintain the rotational force of the separator within the range.